The present invention relates to an apparatus and method for controlling the light-range of the headlights of a motor vehicle.
A known apparatus for control of the light-range of the headlights of the motor vehicle includes an adjusting device connected with the headlights, at least one vehicle load condition sensor, and an analyzer/control unit connected to the adjusting device and the at least one load condition sensor. The load condition sensor or sensors detects the load condition of the motor vehicle and sends a sensor signal containing the information regarding the load condition to the analyzer/control unit which then sends a control signal to the adjusting device which adjusts the light-range.
One apparatus of this kind is described in German Published Patent Application 23 33 983. This apparatus has an ultrasonic sensor, by which the distance between the chassis of the motor vehicle and the road is detected. Adjusting devices are connected with the headlights, by which their inclination or angular orientation is controlled. The sensor produces a sensor signal dependent on the distance of the chassis from the road and thus on the load condition of the motor vehicle. In the analyzer/control unit the sensor signal is processed and the adjusting device is controlled by it so that the light-range of the headlights is maintained constant with all the load conditions of the motor vehicle. In this known apparatus however it is presumed that the headlights have a correct base position when the vehicle is not loaded, from which they are adjusted or moved on loading of the motor vehicle. If the base position of the headlights is however incorrectly set when not loaded, an incorrect adjustment of the headlights results when the headlights are reset with the vehicle loaded.